Introduction

Multilocular prostatic cystadenomas were first documented in the medical literature in 1991, with only 40 cases reported since.^1,2 Symptomatic patients afflicted by this growth typically report lower urinary tract concerns due to local compression. Hesitancy, frequency, and urgency are 3 of the most commonly reported symptoms; others have noted urinary retention, constipation, obstructive azoospermia, and hemorrhoidal pain.² Due to the nonspecific findings associated with these tumors, diagnosis is often not made until pathological examination of a surgical specimen. Average patient presentation age is 50.0 ± 16.3 years,² with 1 case report documenting a case in a 16-year-old boy.³ Surgical removal has been documented as the standard of treatment. Gonadotropin-releasing hormone antagonists have also been shown to treat tumor recurrence after surgery.⁴ More recently, a combination of androgen deprivation therapy and radiotherapy has been shown to be curative in an individual who was a not a candidate for surgical resection.⁵

We report on the case of a 39-year-old man who initially presented with difficulty voiding and irritative bowel symptoms and was eventually diagnosed with a massive prostatic cystadenoma requiring definitive surgical extirpation.

Case Presentation

The patient is a 39-year-old male who presented initially to his primary care provider with a month-long history of gradually worsening lower urinary tract symptoms. He was chiefly concerned with difficulty voiding, noting increased urgency, frequency, and suprapubic pressure unrelieved with bladder emptying. He also reported the absence of ejaculate with orgasm and loose mucous stools. The primary care provider’s workup involved urinalysis, urine culture, and testing for sexually transmitted infections, which were negative. The patient was treated for presumptive prostatitis, given a onetime dose of azithromycin, and told to follow up in clinic in a week.

Persistence of symptoms eventually prompted a more extensive workup involving blood and stool studies. Stool cultures, stool assay, and stool parasitology were all negative. While typical markers of infection and inflammation (white blood cell count, sedimentation rate) from the blood were within normal limits, a PSA level was found to be elevated at 13.584 ng/ml. A CT scan of the abdomen and pelvis was ordered, and the patient was discharged on a 6-week course of trimethoprim-sulfamethoxazole for suspected continued prostatitis. Imaging revealed a 12 × 15 × 17 cm heterogeneous enlargement of the prostate that was concerning for malignancy (Fig. 1). The patient was then referred to urology for further workup and management.

An extensive urological evaluation included cystoscopy, ultrasound of the prostate, biopsy, and aspiration of fluid in the operating room. The results included negative cytology, negative fluid cultures, and prostate biopsy that revealed “benign prostatic tissue with lymphohistiocytic inflammation and focal neutrophilic infiltration.” As the initial biopsies proved negative for malignancy, several CT-guided drains were placed for symptom control in order to reduce some of the pelvic pressure as the patient was counseled and prepared for definitive surgical removal. During this time, an additional CT-guided biopsy of the prostate was performed, which was suggestive of prostatic cystadenoma. Cytological analysis of the drained fluid showed only inflammatory material without malignancy. A pelvic MRI was ordered, which revealed tumor growth, significant upward displacement of the bladder, and rightward displacement of the rectum without obvious invasion (Fig. 2).

Figure 1. Coronal imaging from abdominal and pelvic CT scan revealing extent and heterogeneous composition of large prostatic mass.

Given the displacement of the rectum and sigmoid colon, colorectal surgery was consulted, and surgical resection was planned in combination with both surgical teams. In the weeks prior to surgery, the patient had acute worsening of his urinary symptoms requiring a Foley catheter placement and ultimately bilateral nephrostomy tubes; both offered little symptomatic improvement. Roughly 6 months elapsed between the patient’s presentation to his primary care provider and eventual surgical resection.

Figure 2. Sagittal T2 MRI depicting heterogeneous composition and diffuse pelvic spread of the prostatic mass without obvious invasion.

The operation was conducted through an open midline laparotomy incision. The mass was immediately visualized filling the entirety of the pelvis and displacing the bladder superiorly into the upper pelvis/lower abdomen. The dissection was difficult due to the mass effect of the tumor as well as the neovascularity throughout the pelvis. The bladder neck was divided to elevate and pack the bladder out of the pelvis while both bladder pedicles were mostly preserved. The mass was freed off of the sacral promontory and the surgical team ligated the dorsal venous complex and divided the urethra at the apex of the mass. Both prostatic pedicles were divided as the team gained lateral mobility. Because of the bulkiness of the mass, neurovascular bundle preservation was not achievable. During mobilization of the mass from the pelvis, it became clear that the lesion was intimately associated and inseparable from the rectum from the level of the upper rectum to the pelvic floor. Consequently, proctectomy was required, and reconstruction with a hand-sewn coloanal pull-through with proximal diverting loop ileostomy was performed.

Urethrovesical anastomosis was performed in standard fashion.

Final pathological examination of the tumor revealed it to be a prostatic cystadenoma (Fig. 3). After an uncomplicated 6-day hospital stay, the patient was discharged home. A low pressure cystogram revealed no leak and his Foley catheter was removed. Six weeks after catheter removal, he complains of only 1 security pad per day incontinence and a strong stream. He recently underwent a negative barium enema and is scheduled for ileostomy takedown.

Figure 3. Microscopic view of the pathological specimen demonstrating cystic filled spaces lined with fibrous stroma Hematoxylin & eosin, reduced from ×40.

Discussion

Prostate cystadenomas are very rare, benign prostate tumors.¹ Their growth and resulting compression of local structures causes the primary patient complaint to be lower urinary tract in nature: urine frequency, hesitancy, and urgency. Of the 40 cases currently documented in the literature, most patients have reported some or all of these symptoms.² This constellation of symptoms often resembles other, more common disease processes of the prostate or urinary tract, including infection, benign prostate hyperplasia, prostate adenocarcinoma, or prostatitis, which makes diagnosis exceedingly difficult.

In the case report, the patient’s initial presentation and workup led providers to an initial diagnosis of prostatitis. Only after an elevated PSA value did the provider order a CT scan. Other cases of prostate cystadenoma have struggled with a similar diagnostic approach. Some cases have reported elevated PSA levels, reaching as high as 68.2 ng/ml. Other cases have reported PSA levels in the normal range; still others never even checked the PSA level because it was not indicated based on their patient’s presentation.²

As with our patient, many providers eventually perform a prostate biopsy to shed more light upon the patient’s presentation. Once again, this diagnostic step is often variable in prostate cystadenomas. Most reports in the literature cite biopsies that either showed benign prostatic tissue or indeterminate chronic inflammation.² Imaging is often the next step in workup, revealing the extent and heterogeneous nature of the growth. However, this step is not diagnostic as many other rare or atypical growths can appear similarly. Only histological examination of a surgical specimen is definitively diagnostic.

Surgical resection of these tumors has been documented as the mainstay of treatment. In 39 of the 40 previously reported cases, surgery was the initial treatment approach.² In 2003, Data et al demonstrated that a recurrence of prostate cystadenoma could be successfully treated with the gonadotropin-releasing hormone antagonist leuprolide (Lupron^®).⁴ More recently in 2021, Sushentsev et al reported on the complete resolution of prostate cystadenoma with combined androgen deprivation therapy and radiotherapy in an individual who was not a candidate for surgery.⁵ While these reports indicate that hormone therapy could be considered for salvage or even adjuvant therapy, surgical resection remains the mainstay of treatment.²

The prognosis of individuals diagnosed and treated for prostate cystadenomas remains favorable. Only 2 documented individuals have had a symptomatic recurrence, potentially related to incomplete surgical resection. The first, discussed above, was treated without surgical reintervention.⁴ The second underwent laparoscopic removal of the recurrent growth without any residual sequelae.⁶

Conclusion

We present our case of giant prostate cystadenoma that displayed extensive pelvic mass effect and associated symptomatology. While rare in occurrence, this benign growth needs to be considered in the differential diagnosis for patients with voiding or defecation symptoms whose etiology is otherwise undetermined, especially with an unusual prostate mass noted on imaging. Prompt intervention for symptomatic relief while planning eventual complete surgical resection is necessary to prevent delayed treatment courses. A multidisciplinary surgical approach with urology and colorectal surgery should be anticipated to optimize outcomes.

Conflicts of Interest

The Authors have no conflicts of interest to disclose. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.